What is prevention?

Cancerprevention is action taken to lower the chance of getting
cancer. By preventing cancer, the number of new cases of cancer
in a group or population is lowered. Hopefully, this will lower
the number of deaths caused by cancer.

To prevent new cancers from starting, scientists look at risk
factors and protective factors. Anything that increases your
chance of developing cancer is called a cancer risk factor;
anything that decreases your chance of developing cancer is
called a cancer protective factor.

Some risk factors for cancer can be avoided, but many cannot.
For example, both smoking and inheriting certain genes are
risk factors for some types of cancer, but only smoking can be
avoided. Regular exercise and a healthy diet may be protective
factors for some types of cancer. Avoiding risk factors and
increasing protective factors may lower your risk but it does
not mean that you will not get cancer.

Anal cancer is a disease in which malignant (cancer) cells
form in the tissues of the anus.

Anatomy of the lower digestive system, showing the colon and other organs.

Anatomy of the lower digestive system, showing the colon and other organs.

The anus is the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. The anus is formed partly from the outer skin layers of the body and partly from the intestine. Two ring-like muscles, called sphincter muscles, open and close the anal opening and let stool pass out of the body. The anal canal, the part of the anus between the rectum and the anal opening, is about 1-1½ inches long. Anatomy of the lower digestive system, showing the colon and other organs.

The skin around the outside of the anus is called the perianal area. Tumors in this area are skin tumors, not anal cancer.

Squamous cell carcinoma is the most common type of anal cancer.

Another type of anal cancer, called anal adenocarcinoma, is very rare and is not discussed in this summary.

In the United States, the number of new cases of anal cancer has increased in recent years.

From 2001 to 2010, new cases of anal cancer and deaths from anal cancer increased each year. The increase in new cases was slightly higher in women and the increase in deaths from anal cancer was slightly higher in men.

Avoiding cancerrisk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. Increasing protective factors such as quitting smoking, eating a healthy diet, and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.

The risk of anal cancer is higher in men who are HIV-positive and have sex with men compared with men who are HIV-negative and have sex with men. Women who are HIV-positive also have an increased risk of anal cancer compared with women who are HIV-negative.

Studies show that intravenousdrug use or cigarette smoking may further increase the risk of anal cancer in patients who are HIV-positive.

Immunosuppression

Immunosuppression is a condition that weakens the body's immune system and its ability to fight infections and other diseases. Chronic (long-term) immunosuppression may increase the risk of anal cancer because it lowers the body's ability to fight HPV infection.

Having an autoimmune disorder such as Crohn disease or psoriasis may increase the risk of anal cancer. It is not clear if the increased risk is due to the autoimmune condition, the treatment for the condition, or a combination of both.

Certain sexual practices

The following sexual practices increase the risk of anal cancer because they increase the chance of being infected with HPV:

Having receptive anal intercourse (anal sex).

Having many sexual partners.

Sex between men.

Men and women who have a history of anal warts or other sexually transmitted diseases also have an increased risk of anal cancer.

Cigarette smoking

Studies show that cigarette smoking increases the risk of anal cancer. Studies also show that current smokers have a higher risk of anal cancer than smokers who have quit or people who have never smoked.

The following protective factor decreases the risk of anal cancer:

HPV vaccine

The human papillomavirus (HPV) vaccine is used to prevent anal cancer, cervical cancer, vulvar cancer, and vaginal cancer caused by HPV. It is also used to prevent lesions caused by HPV that may become cancer in the future.

Studies show that being vaccinated against HPV lowers the risk of anal cancer. The vaccine may work best when it is given before a person is exposed to HPV.

It is not clear if the following protective factor decreases the risk of anal cancer:

Condom use

It is not known if the use of condoms protects against anal HPV infection. This is because not enough studies have been done to prove this.

Cancer prevention clinical trials are used to study ways
to prevent cancer.

Cancer preventionclinical trials are used to study ways to
lower the risk of developing certain types of cancer. Some
cancer prevention trials are conducted with healthy people who
have not had cancer but who have an increased risk for cancer.
Other prevention trials are conducted with people who have had
cancer and are trying to prevent another cancer of the same type
or to lower their chance of developing a new type of cancer.
Other trials are done with healthy volunteers who are not known
to have any risk factors for cancer.

The purpose of some cancer prevention clinical trials is to
find out whether actions people take can prevent cancer. These
may include eating fruits and vegetables, exercising, quitting
smoking, or taking certain medicines, vitamins, minerals, or
food supplements.

New ways to prevent anal cancer are being studied in clinical
trials.

Clinical trials are taking place in many parts of the country.
Information about clinical trials for anal cancer prevention can be found in the Clinical
Trials section of the NCI Web
site.

Get More Information From NCI

Call 1-800-4-CANCER

For more information, U.S. residents may call the National Cancer Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 8:00 a.m. to 8:00 p.m., Eastern Time. A trained Cancer Information Specialist is available to answer your questions.

Chat online

The NCI's LiveHelp® online chat service provides Internet users with the ability to chat online with an Information Specialist. The service is available from 8:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. Information Specialists can help Internet users find information on NCI Web sites and answer questions about cancer.

The NCI Web site provides online access to information on cancer, clinical trials, and other Web sites and organizations that offer support and resources for cancer patients and their families. For a quick search, use the search box in the upper right corner of each Web page. The results for a wide range of search terms will include a list of "Best Bets," editorially chosen Web pages that are most closely related to the search term entered.

There are also many other places to get materials and information about cancer treatment and services. Hospitals in your area may have information about local and regional agencies that have information on finances, getting to and from treatment, receiving care at home, and dealing with problems related to cancer treatment.

Find Publications

The NCI has booklets and other materials for patients, health professionals, and the public. These publications discuss types of cancer, methods of cancer treatment, coping with cancer, and clinical trials. Some publications provide information on tests for cancer, cancer causes and prevention, cancer statistics, and NCI research activities. NCI materials on these and other topics may be ordered online or printed directly from the NCI Publications Locator. These materials can also be ordered by telephone from the Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237).